1. Technical Field
The present principles relate to air conditioning devices. More particularly, it relates an electrostatic air conditioner.
2. Discussion of Related Art
Electrostatic air purifiers and conditioners are known and often utilize parts referred to as “corona” wire or “corona electrode”, “collecting electrode”, and barriers between these electrodes. These parts are contained within a housing, while the corona electrode and the collecting electrode are most often removable from the housing for periodic cleaning. The barriers serve to protect a sparkover or creeping (along the surface) discharge between the electrodes.
In other known devices, an ion collecting member (Collecting cartridge or collecting electrode) and an ion emitting member (Corona electrode or corona frame) are supported on the floor of the housing.
In both of the above designs the electrodes are attached flush to the walls of the housing in order to prevent dirty air from bypassing between the electrodes and the walls.
The disadvantage of such designs is that contaminating matter (vapor or particles), containing chemically aggressive or electrically conductive matter enters into the housing with the air and settle on the barriers, housing's floor and/or on the walls.
Such an aggressive or conductive matter contaminates plastic barriers and walls and makes them electrically conductive. After a while the contamination is difficult or even impossible to remove. Being chemically aggressive this matter penetrates deeply into plastic body and changes non-conductive material's (like ABS) physical properties making it semi-conductive material. The barriers and walls being semi-conductive shorten the distance between the electrodes and provoke the electrical discharge (spark or creeping discharge) between the corona wire and the collecting electrode.
When the device is new (and barriers are non-conductive) the air gap between the corona frame and the collecting cartridge is equal to D. The gap D is selected of such length that no electrical discharge like spark or arcing between the electrodes takes place while the corona discharge occurs and ions are emitted from the corona electrode to the collecting electrode. When the barriers between these electrodes become semi-conductive the ions emitted from the corona wire travel to the barrier's top. This ions' flow constitutes an ionic current flowing from the corona electrode to the barrier. The barrier then assumes the electrical potential that is close to the electrical potential of the corona wire effectively shortening the gap D. The same event happens when particles settle on the walls.
In this event an electrical discharge may occur from the barriers' edges (or from the contaminated walls) to the collecting cartridge. This unfortunate event shortens the lifetime of electrostatic air conditioning systems when they are employed in certain geographical, industrial or climatic regions with chemically aggressive or electrically conductive contaminations present in the air.
In the prior art, the corona frame is made of electrically insulating material (plastic). On this frame thin corona wires are located. The wires are parallel to each other. At the bottom and at the top of the corona frame the conductive wires meet and touch an electrically insulating material of the frame. The electric field strength at the spot where two materials touch each other is substantially higher than in the middle part of the wires. To alleviate the electric field raise additional insulating barriers are installed on the frame. These barriers are located at the side of the corona frame that is closest to the opposite electrodes.
The disadvantage of such design is the same as above, i.e., the dust, containing chemically aggressive or electrically conductive matter (vapor or particles), enters into the air conditioner and settles on the corona frame barriers.
When the barrier becomes semi-conductive, the ions emitted from the corona wire go to the corona frame barriers' edges. The barrier then assumes the electrical potential that is close to the electrical potential of the corona wire, effectively shortening the gap between the corona electrodes and the collector electrodes.
Therefore some “hissing” and even sparking may occur from the barrier edges (or from the contaminated walls) to the corona or collecting electrodes. Again, this unfortunate event shortens the lifetime of electrostatic air conditioning system that works in certain geographical, industrial or climatic regions where chemically aggressive or electrically conductive contaminations are common in the air.
Another drawback to existing corona frame designs is the wire vibration that occurs from time to time and which causes unpleasant noise, as well as may lead to the wire degradation and damage.
Still another previous art disadvantage is that when a corona wire needs a replacement, the whole frame is disposed or new wires are attached to the frame by rather cumbersome and time consuming process. This increases cost and maintenance expenses.
Still another disadvantage of the existing air conditioners is that some undesirable electrical discharge may take place when foreign matter is trapped between the electrodes or the electrodes became dirty.
Therefore there is a need for simple yet reliable mean for undesirable discharges detection.
The electrostatic air conditioning system of the present principles is free of the above-noted deficiencies.